Telephone-exchange system.



"E. E. CLEMENT.

TQLEPHONE EXCHANGE SYSTEM. APPLIOATION Finn-JULY 14, 1906. RENEWED JULY 20, 1914.

1,109,51 1 Patented Sept. 1, 1914.

3 SHEETSSHEET 1.

Wi :11 wow E. E. CLEMENT.

' TELEPHONE EXCHANGE SYSTEM. APPLIOATION'IILED JULYM, 1906. RENEWED JULY 20, 1914.

Patented Sept. 1,1914.

3 SHEETS-SHEET Z.

atwzntoz B. E. CLEMENT.

TELEPHONE EXCHANGE SYSTEM. APPLICATION FILED JULY 14, 1906. RENEWED JULY 20, 1914 1,109, 51 1 Patented sept. 1, 1914.

3 SHEETS-slings.

S nvewfoz unrrnn STATES. PATENT OFFICE.

EDWARD E. CLEMENT, or wn smne ron, ms'rmcrr or corumiam, Assmnon, BY mxsnn assrcnmnnrs, T FREDERICK o. srnvnns, or ATTICA, new roan.

rnLnrr-ronn-nxcnanon SYSTEM.

' Specification. of Letters Patent.

Licamr.

Patented Sept. 1, 1914..

Application filed July 14, 1906, Serial No. 3%,253. Renewed July 20, 1914. Serial No. 852,087.

Toall whom it mag concern Be it known that I, EDWARD E. CLEMENT,

a citizen of the United States, residing at Washington, in the District of Columbia,

have invented certain new and useful Improvements in Telephone-Exchange Systems, of which the following is a specification', reference being had therein to the accompanying drawing.

My invention relates to telephone exchange systems and has for its object the improvement of automatic systems by the substitution. of relays 'for step by step )The' system which I shall hereinafter spe 'cifically :desc'ribe' is a full automatic system,

that is, fone in which the control of'the relays is effected. from'the subscribers station, but the general'arrangement may also be applied to semi-automatic systems, in which the Workof setting up the switches or relays is done by an operator at the central office.

It will be observed after study of the ac companying drawings that no charZ-gl will be required in the mechanism or circuits in order to make the I system semi-automatic, since I use only two wires and no ground for a subscribers line, and have a perfectly clean metallic talking circuit throughout,

Briefly stated, my lnvention comprises means at a subscribers station of making and breaking his metallic line circuit, means associated with his line at the central ofiice to translate these makes and breaks into current impulses on one side or the other of a switch or relay circuit, whereby the line may be connected to other lines. I terminate the line extension preferably in a set of relays, but I need not identify any special relay set in any particular line. since any two lines having terminals in the same set of relays may be connected together by energizing the prdper relays simultaneously. Taking the decimal or double digitsystem, suppose we have two lines numbered 97, and 64, respectively, which it is desired to connect togeth'er. This may be effected by pulling down the number 90 relay, the number relay. thenumber 7 units relay, and

calling line proi ided with a complete set of relays whereby it can reach any other line. To call line number 97, for example, the

subscriber would send .nin'e impulses followed by seven impulses. These nine impulses I cause to step up nine selecting re-- lays successively, the ninth one of which closes the circuit of the number 90 lens relay of the connector group; by means of the central oflice line relay then, I send a single impulse which changes the selector relays and gives them control of the units relays of the connector sct. They then step up in response to the seven impulses until they have picked out the number 7 units relay, and the combination of 90 and 7 gives the desired connection.

The feature of having step b st 1 -.:;i. (j-

- rectly controlled by an electromagnet or its equivalent in another.

apparatus. Fig. 2 shows a portion of the trunk with a set of step by step relays. Fig. 3 shows a set of connector relays controlled by step by step relays in Fig. 2.

.Referring now to Fig. 1, the subscribers station comprises the usual apparatus consisting of the transmitter, receiver, ringers, condenser and switch-hook. In addition to the foregoing, I have added a. simple make and break device for sending impulses to the central ofiice. This device is represented diagrammatically by the push button P hav ing the normally closed contacts 19 and 19. When the push button is depressed, the con tact springs and -p are broken, thus opening the line as the telephone is connected to the line through these contacts. At the central office the relays D and D are bridged across the conductors 5 and 6, the relay D being connected to the grounded side of battery, while the relay; D is connected to the free side of battery. These two relays besides furiiishing talking current to the calling subscriber also control the two solenoids or slow-acting relays X and X, and the joint action of the relays D and D and these solenoids control the relays in the set W, Fig. 2, and these in turn control. or select the relays in The solenoids X and X are quick acting when energized, but after they are energized, their cores drop down slowly and operate their respective contact springs. In place of these solenoids I may substitutea slow-acting relay which can be made sluggish either by mechanical means or, by slipping a copper sleeve over the core. gized when the subscriber removes his receiver. The relay D closing the contacts d and 03, completes the circuit of the solenoid X, which thereupon becoming energized draws up its core, closing the contacts a: and a" and placing battery on the contact (Z. The solenoids X and X while responding to quick makes and breaks of the contacts in the relay D, do not allow their cores to dro down during these makes and breaks. Itiollows, of course, that any makes and breaks at the subscribers station caused by manipulating the push button P while atfecting the relays D and D, only cause the solenoids to remain energized with' their cores drawn up. The solenoid X hasits circuit closed during these makes and breaks on account of battery bein placed on the contact d by the solenoid During the entire conversation and while impulses are being transmitted, the solenoid X remains energized while the solenoid X only remains energized, while the impulses are being transmitted. At the end of a set of impulses when the relay D is energized, the circuit-of the solenoid. X is open and, becoming deenergized, its core drops down and momentarily closes the contacts m and 00 thereby placing a grounded impulse on the wire contacts cl and d. The relays E and attached to the trunk wires 7 and '8 and separated by the condensers C and C from the answering end of the trunk'furnish bat tery to the called subscriber and control the ringing relay Y.

Referring now to Fig. 2, the two relays E-and E which respond to the operating impulses and the switching impulses, respectively, directly control the relays F, F and. the relays of the set W. The operation of the relay E closes the circuit of the relay F which supplies battery to the contact e of the relay E. vThe making and breaking of the contacts e, e and e operate the relays of the set W in stepby step order. The first impu se coming in energizes the relay E, but while this relay is in an energized condition, none ofthe relays in the set W are afi'ected, but after the impulse has passed, the circuit of the relay H is closed .through the contacts a and e as battery has The relays D and D becomeener-.

which leads to the relay E, Fig. 2. The operatihg impulses are transbeen placed on contact 6 by the energizing of the relay F. The operating of the relay H closes the circuit of the relay VV through the contacts it and it. Now, when the second impulse comes in and the relay E is in an energized condition, the circuit of the relay W is closed through the contacts 6 and e-. After the impulse has passed, the circuit of the relay H is closed through the contacts to and w of the relay W". This relay T while the relays V W and W control the relays T,T and Tirespectively. The relays T, T etc., in the upper row are the tens relays and each contains the multiples of ten lines. For a 100 line system there would be ten of these relays. The

drawing only shows five of these relays, the remainder being similarly arranged and their operation being identical. I have shown the relays in this manner for simplicity as additional wiring would be con fusing. The lower set of relays T T etc., are the units relays and each contains multiples of the contacts. of the up er set or tens relays. The relay T being t e first units relay, contains the -multiples of the first pair of contacts in each of the tens relays T, T etc, while the relay T contains the multiples of the second pair of contacts of the tens relays. The trunk wires 7 and 8 are alsomultipled to contacts in the lower set or units relays. If the first tens relay T and the first units relay T are energized, the trunk wires 7 and 8 would be connected to line 11 through the contacts 6- and the first pair of contacts t, and if the third tens relay T and the second units relay T were energized, the trunk wires would be connected toline No. 32 through the contacts and the second pair of contacts The tens relays are the first set of relays to be operated by the relay set W and are provided with two windings, an actuating winding which is controlled by the relay F and also a lockin winding which is controlled bythe same re ay. The locking winding of the relay is connected to the common 'wire 16 leading to the contacts f F, while the actuating windings are connected to the common wire 15 leading to ground through the contacts f and f of the relay F. Individual a tuating wires 23, 24, 25, 26

[and 27 lead to the normally open contacts of the relays WV, Wflctc. The units relays in the relay the selected units relay.

modem are only provided with a single winding and are operated after the tens set in their proper order. The winding from the first units relay T is connected in multiple with the a'ctuatin winding of the relay T to the wire 23. he winding of the relay T is connected to the wire 24: in multiple with the actuating winding of the relay T while the relays T, T and T are connected in multiple respectively to the actuating windings of the relays T T and T The other terminal of each of the units relays is connected to the common wire l-l leading to the normally open contact f of the relay F. From the foregoing description it will be seen that if battery is placed on wireQS by the relay W, the relay T will be operated, be ng: connected to ground through the contacts of the relay F, but the relay T will notlie affected as the common wire 14 is disconnected from ground. The relay F is in reality the switching relay and is operated after the first set of impulses by the grounded impulse being sent over the wire 50 by the solenoid X. This impulse directly affects the relay E which in turn closes the circuit of the relay F which remains locked through the contacts f and f and under the control of the solenoid X. The operation of the relay F removes ground from the common wire 15 of the tens set of relays and connects ground to the common wire 14 .of the units set of relays. This relay also by closing the contacts f" and f places battery on the locking wire 16 which thereupon keeps the tens relay which was last operated in an energized condition. When the grounded impulse is sent over the wire 50 operating the relay E, the contacts (2 and e are broken, releasing the relay F which thereupon removes battery from the commonwire 13 leading to the locking contacts of the relays in the set W. The relays of. the set Ware thus restored to their normal position and ready to be operated a second time to select or pick out the proper units relay. .The operation of the relays W the second time is the same as already described the only difference being that after the second set of impulses the relays are not released, for the grounded impulse coming in after the second set of impulses fails to 0perate the relay E as it is disconnected from battery at this time on account of the relay F being ener izcd and breaking the contacts f and f. These relays of the set W'relmaining energized after the second set of impulses enable me to use a single Winding on the units relays as battery remains on the particular individual wire leading to After the second set of impulses} the trunk is connected through to the desired line and the relay Y, l becomesenergized in series with the intern pting machine which is common to a contact in each of the units relays. The re lay Y connects generator to the called line 'and at the same time opens the answering .end of the trunk.

When the called subscriber answers the relay E becomes en'en gizcd and disconnects the ringing relay Y. At the end. of the conversation the calling subscriber hanging up his receiver deenergizes the relays D and D allowing the solenoid X to drop its core thereby removing battery from the holding wire 9 thereby releasing all the relays, and the apparatus is restored to its normal condition.

The operation of my system is as follows: The subscriber at station A removing his receiver closes the circuit of the relays D and l). The relay D closes the circuit of the solenoid X. by the following path: battery B, 63, (Z (Z 54, X to ground. This solenoid in turn places battery on the contact d by the closing of the conla.ct;-; a" and in. The subscriber now proceeds to set up the sendin; device which thereupon makes and breaks the contacts 71 and 7) a number of times corresponding to the number desired. Suppose the number to be sent wa 32. The subscriber would first set up the device to i\o. 3 which upon running down makes and breaks the contacts [I and 2. These makes and breaks operate the relays Band D a number of times corresponding to. the numher to be sent. The first impulse affecting the relay D is repeated to the relay E over the wire 20 through the contacts 01 and (Z. The rclay E becoming energized, closes the circuit of the relay F by the following path: battery B, 21', e e 22,1 to ground. The operation of this relay places battery on the contact byl the following-path: battery B, 21,, 0, 1, 28, f, f", 13 to c. The relay F also places battery on the extension wire 13 which is common to all the locking contacts of the relays in the set W. Battery is now placed on the wire 18 through the contacts sand 6 but the contact h of the relay H is open at this juncture and the relay WV is not affected. After the first impulse the relay E becoming deenergized closes the contacts c and e placing battery on the Wire 1!) through the contacts w and w to the relay H and ground. The relay H thereupon becomes energized and locks itself through the contacts 7L2 and 71- leading to the locking wire 13. The contacts I: and h traced. After the second impulse the contacts 'e" and 6 being closed, the circuit of the relay H is completed through the contacts a and 111 ofsthe relay W. The first impulse which comes in does not operate any ground to battery. In the relay E .common wire 15 of the tens simply close the circuit of the relay H second, the relay H through the contacts to and 10 of the relay The fourth impulse operating the relay E closes 'the circuit of the relay W and H*. When the relay W was operated at the second impulse the -circuit of the first tens relay T was closed by the following path:,,battery B, 21, Q0 10 zo an 217 22, lii i l, e, e 23 T! 15, f*, f to ground. This relay T does not remain locked as the common locking wire 16 is open in the relay F. At the third impulse the operation of the relay W closes the circuit of the relay T over the Wire 24 and at the same time opens the circuit of the relay T by breaking the contacts w? and w. At the fourth impulse the relay W operat ing closes the circuit of the relay T and at the same time opens the circuit of the relay .1 by breaking the contacts w and w. The relay T contains the "contacts of the desired line and during the interval it takes the.

subscriber to set up the second digit, the circuit of the solanoid X is opened at the contacts 03 and (Z and the core dropping down closes the contacts 00 and :0 thereby placing a grounded impulse on wire 50 .This impulse closes the circuit of the relay-E by way of d (Fig. 1), (into Fig. 2), E, f, f, 12, 21, B and ground, which in turn close the circuit of the relay F by way of B, 21, e 17, F and the opening of the contacts e and e and e and e disconnects the rela F and releases all of.

the relays in the set \V. The operating of the relay F connects battery to the wire 16 which maintains the circuit of the relay T which is energized at this time. The relay T is the only one of the'set that can-be afi'ected by battery-being placed on wire 16 as its locking circuit is connected to ground through the contacts 250 and 200 respectively. Ground is now removed from the relay by the openingof. the contacts f and f and ground is connected to the common wire 14; of the units relay. The relay set W is now again in position to be operated by the second set oit', impulses, the only difi'erence being that the units relays are now controlled in place of the tens relay's- The subscriber now sends in the proper set of impulses to select the second units relay T". The relays in the set W are operated in the same manner as be 'rality of line circuits,

fore and when the relay Vi is selected the A circuit of the relay T is closed through the wire 24. The calling subscriber is now conthrough the same contacts t and If to the trunk wire 8, and so into Fig. 1 and back to I generator. When the'called party answers, the relay E is energized cutting off the ring ing relay Y. At the end of the conversa tion the calling subscriber hanging up his receiver denergizes therelays D and D,

allowing the core or the solenoid X to drop down. After the core "of the solenoid has dropped down, the contact springs a and w are disconnected, removing battery from the wire 5),thereby releasing the relays F and F which inturn release the relays in the set W which turn disconnect the tens and units relays, thus restoring all the apparatus to its normal condition.

Having thus described my invention, what Iclaim and desire to secure by'Letters Patent is :v I

1. In a telephone exchange system, a plurality of line circuits, a group of relays containing contacts connected so as to'form combinations adapted to directly interconnect the said line circuits, and means associated with the line circuits fOr'sending a series of selective impulses of a predetermined total number to control the said relays, substantially as described. I

12. In a telephone exchange system, a plua plurality of relays having contacts adapted to directly interconnect the said circuits, and means for selectively controlling the said relays through the line circuits by means of a predetermined total number of ci'irrent impulses sent thereover,-substantially as described.

3. In a telephone exchange system, a plurality of line circuits having substation and central station terminals, with impulse transmitters at the former, and switching sets at the latter composed exclusively of tens and units relays, and circuit. connections whereby said impulse transmitters may act selectively and successively upon-the tens and units re ays of the relay gets through the line circuits, substantially as described.

4. In a telephone exchange system, a sub-" scribers station and a central station and a line circuit interconnecting the same, auto matic switching relays for cnnnecting the 7 means for selectively la'ys, substantially as described.

' interconnect the lines,

said relay line with other lines, a separate step by step number selecting device for said switching relays, and means at the subscribers station for setting said step by step device through the line circuit so as to predetermine the connection to be made by the switching relays, substantially as described.

q 5'. In an automatic telephone system, the combination of a line circuit having automatic switching apparatus at the central station for interconnecting it with other line circuits, a set of step by step number selecting'rclays for said switching apparatus, and:

controlling said relays by current changes in the line circuit,'su stantially as described,

6.- In an automatic telephone exchange system, a plurality of line circuits, a'plurality of relay connector sets for interconnecting the same, a plurality ofstep by step relay sets controlling the connector sets, and subscribers impulse sending devices "for actuating the controllingrelays, substantially as described.-

7fln an automatic telephone exchange system comprising metallic circuit lines, fast and slow relays ior each line responsive to makes and breaks in the metallic circuit only, relay connectors for the lines, andstep by step mechanism adapted to actuate connectors and selectively controlled by the fast and slow relays, substan tially as described.

I 8. In an automatic telephone system, a lurality of metallic circuit subscribers ines, a device at each sub-station to make and break its metallic circuit, a relay at the centralloificeres ending to the makes and breaks, a plura ity of selector relays con trolled by said relay and a plurality of connector relays controlled by the selector re- 9. In an automatic telephone. plurality of subscribers lines, relays having contacts included in and adaptedto directly ers adapted tosend a predetermined total system, a

andsubscribers sending a group circuit,

same, a. make and break device in the me tallic circuit su'bscribersline, and means responsive to makes and breaks in the line for controlling said relays, scribed. l

11, In an automatic telephone system a metallic circuit suhscribers linc,---means for connecting said line with other lines includof step-by step relays, and means at the subscribers station for making and substantially as debreakin'gthe metallic circuit and thereby actuating said relays, substantially as described. .T v v 12. Inan automatic telephone system, a metallic circuit, subscribers line, a central station, automatic switching mechanism at said central station, said switching mechanism consisting of a series of relays, a pair of controlling .relays having different time constants associated with said switching re lays, and being themselves controlled by makes and breaksin thesubscribers linev 13, n an automatic telephone system, subscribers line circuits, impulse sending devices thereat, a quicli acting relay at the central station for transmitting said impulses, a pair of controlling relays 1'esponsive to said impulses, one oi said relays be ing a slow acting relay, and an automatic switch comprising a seriesof relays adapted to efiecta' talking connection between the subscribers lines in response to said controlling relays. h

In testimony whereof if affix my signature in presence of two Witnesses. 4 EDWARD E. CLEMENT.-

Witnesses:

E. EDMONBTON, ,ln, L. BABCOCK.

the action of 

